[gcc r11-9899] libstdc++: Avoid -Wzero-as-null-pointer-constant warning [PR103848]

[Jonathan Wakely]

https://gcc.gnu.org/g:b59435ff6069583290c8e0953a58044f598a348c

commit r11-9899-gb59435ff6069583290c8e0953a58044f598a348c
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Jan 4 21:57:16 2022 +0000

    libstdc++: Avoid -Wzero-as-null-pointer-constant warning [PR103848]
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/103848
            * include/bits/stl_deque.h (operator-): Do not use 0 as null
            pointer constant.
    
    (cherry picked from commit 76a45931ab7c831e32cebf13a6317e5e142f8151)

Diff:
---
 libstdc++-v3/include/bits/stl_deque.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/libstdc++-v3/include/bits/stl_deque.h b/libstdc++-v3/include/bits/stl_deque.h
index 20c73b4fc3c..8236fe35ce7 100644
--- a/libstdc++-v3/include/bits/stl_deque.h
+++ b/libstdc++-v3/include/bits/stl_deque.h
@@ -353,7 +353,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       operator-(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
       {
 	return difference_type(_S_buffer_size())
-	  * (__x._M_node - __y._M_node - int(__x._M_node != 0))
+	  * (__x._M_node - __y._M_node - bool(__x._M_node))
 	  + (__x._M_cur - __x._M_first)
 	  + (__y._M_last - __y._M_cur);
       }
@@ -365,10 +365,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       template<typename _RefR, typename _PtrR>
 	friend difference_type
 	operator-(const _Self& __x,
-		  const _Deque_iterator<_Tp, _RefR, _PtrR>& __y) _GLIBCXX_NOEXCEPT
+		  const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
+	_GLIBCXX_NOEXCEPT
 	{
 	  return difference_type(_S_buffer_size())
-	    * (__x._M_node - __y._M_node - int(__x._M_node != 0))
+	    * (__x._M_node - __y._M_node - bool(__x._M_node))
 	    + (__x._M_cur - __x._M_first)
 	    + (__y._M_last - __y._M_cur);
 	}